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No. 6l6,993. Patented .Ian. 3, I899. E. T. TBEFETHEN.

TRIP JACK.

(Application filed July 18, 1898.) (No Model.) 2 Shouts-Shae! I.

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7260M 53m. 4Jllfllli Eruz'm TTr'gif/wn Patented Jan. 3, I899. E. T. TBEFETHEN.

TRIP JACK.

(Application filed July 18, IBQBA 2 Sheets-Sheet 2.

Z is 274 No. 6l6,993.

(No Mugal.)

1 Q fi V V B V 47 A W. I V M M C T W W llnrTnn STATES PATENT @FFiClE.

ERVIN T. TREFETIIEN, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO ARTHUR O. NORTON, OF OOATIOOOK, CANADA.

TRIP-JACK.

SPECIFICATION forming part of Letters Patent No. 616,993, dated J 'anuary 3, 1899. Application filed July 18, 1898. Serial No. 686,228. (No model.)

To all whom it may concern.-

Be it known that I, ERVIN T. TREFETHEN, of Boston, in the county of Suffolk and State of Massachusetts, have invented a new and useful Trip-Jack, of which the following is a specification.

Reference is had to the accompanying drawings, in which- Figure 1 is a side elevation of mynewjack and shows the lifting-bar partially raised, with the locking-block under one tooth and the lifting-pawl under a lower tooth in position to raise the lifting-bar upon depression of the outer end of the jack-handle. Fig. 2 is a transverse sectional view on line 2 2 of Fig. 1. Fig. 3 is a front elevation of thejack with the lifting-bar in the position shown in Fig. 1. Fig. 4 is a central vertical section of the jack in line 4 4 of Fig. 1. In the foregoing views the jack is shown in condition for lifting. Fig. 5 is a side elevation of the jack, showing the pawl and locking-block out of working position and the handle in its temporary connection with the compound lever which moves the locking-block out of engagement with the teeth on the lifting-bar. The lifting-bar is in its lowest position and has fallen automatically as the locking-block has been moved clear of the under side of the tooth just above it. Fig. 6 is a plan View of the cam side of the handle detached. Fig. 7 is a plan view of the pawl detached. Fig. 8 is a perspective View of the compound lever detached. Fig. 8 is a perspective View of the locking-block detached. Fig. 9 shows a modification in which the cam-receiving opening of the pawl is interiorly faced with a ring forced therein.

The main object of my invention is to produce a jack the lifting-bar of which is automatically lowered without first lifting the load. In all automatically-lowering jacks heretofore made the load has to be lifted before the lifting-bar falls. Jacks of this class are frequently called track-jacks, because they are frequently used for raising the rails of railway-tracks, and it is of very great importance that these jacks should be readily and quickly removed when they are used for raising rails over which trains pass during track repairs. If, for example, the load becomes so great on the lifting-bar that the workmen cannot remove the jack quickly on the approach of a train, serious accidents are likely to occur. In the prior jacks referred to the loaded lifting-bar is raised (to release the lifting-bar) commonly by a dog or pawl working on a fixed axis and engaging a tooth or projection on the lifting bar. Consequently the dog or pawl moves in the arc of a circle, and as the load is on the free end of the pawl or the like the load has to be lifted before the pawl can be moved clear of the lifting-bar.

In the drawings, illustrating the principle of my invention and the best mode now known to me of applying that principle, A is the jack-standard, formed with a lengthwise-extending guideway a for the lifting-- bar B, which is provided with the usual head I) and outwardly-prjecting foot I). The lifting-bar is smooth on its outer front side and is confined in guideway C6 by the bridge-wall a, the under edge of which overhangs foot b and consequently serves to limit the upward movement of the lifting-bar. The outer or front side of the standard' that is, the side away from which the foot 7) projects is made, preferably, straight and free from pro jections, so that there is nothing to prevent lifting a load on the foot for practically the whole distance through which the foot travels. This constitutes one of the advantages of my new jack; but the main feature of my invention lies in the release of the lifting-bar without first lifting the load. To accomplish this important object, I mount the horizontally-movable locking-block B in the horizontal guideway a which is formed in the head of standard A, the block B being movable horizontally into and out of engagement with the teeth I) on the inner side of the lifting-bar. Guideway a is made enough wider than the locking-block to permit the latter to be moved far enough away from the liftingbar to be out of engagement with the teeth thereon.

\Vhile a great variety of devices under the control of the operator may be used to reciprocate the locking-block laterallyinto and out of engagement with the teeth 19 I prefer to use for that purpose a compound lever which is independent of the handle during the lifting operation and which is temporarily connected with the handle for the automatic lowering of the load. Such preferred apparatus consists of the following parts: A lever D, formed with a head (1, which spans the standard and is formed on each side of the standard with a notch d to engage both edges of the locking-block at each projecting end U is mounted on a fulcrum-pin (1 through the head of the standard. The head d is preferably enlarged on the outer side of the fulcrum 01 so that its weight will move the lever on its fulcrum as often as during the lifting operation, the apex of a tooth is moved past the opposing inner edge of the locking block. The lifting-bar is raised tooth by tooth by the pawl F, loosely mounted on the cam f, which is fast on the inner end of the handle F. IIandle F, carrying pawl F, is fulcrumed on a pin f through the rearwardlyprojecting wings a of the standard. By moving the handle up and down the position of the cam in relation to the inner opposed toothed edge of the lifting-bar is changed, so that the pawl is therebypushed against the under side of a tooth to raise the bar and then retracted to engage a next lower tooth. Before the pawl is retracted out of engagement with a tooth the Weighted lever causes the horizontallyreciprocating locking-block B to move under a tooth above the tooth with which the pawl is in engagement, and the lifting-bar is thereby held from descending while the pawl is out of engagement with a tooth on the lifting-bar. It will be observed that the load during the lifting operation is alternately on the pawl and locking-block. To lower the load automatically, it is of course necessary to move the locking-block out from under a tooth and to get the pawl out of the way of the teeth on the lifting-bar. Consequently the pawl is so shaped as to be pulled back out of the way of the teeth, and is desirably provided with a rearward projection or handle f for the more convenient manipulation of the pawl. While the pawl is out of the way of the teeth on the raised lifting-bar and the load is on the locking-block the lower end of the leverD is moved rearwardly, preferably by connecting the lever member D with the hook f which projects from the handle F forwardly past one wing of the standard. (See Fig. 5.) A downward movement of the outer end of handle F will now push the locking-block from under a tooth, and the weight of the lifting-bar itself, to say nothing of a load thereon, will cause the lifting-bar to fall by gravity, so that the load is in this sense automatically lowered. I find in practice that one man can by my new jack release a load which requires four men to lift, and this is a very important consideration, for if it requires as many or nearly as many men to release a loaded lifting-bar of an automatically-lowering jack as are required to lift the load then there is grave danger of the jack being stuck when it 1s desired to lower the jack instantlyas in the case of the swift approach of a train, for example. I prefer to form the cam integral with the handle and to face it with a ring a: of steel of suitable quality to give durability to the structure, shrinking the ring in place on the cam-body; but, if desired, the pawl-receiving opening of the handle maybe interiorly faced with a steel ring forced therein.

If desired,the locking-block may be moved into and out of position by hand, and it is obvious that the locking-block and its guideway may be formed and operated in many ways Without departing from my invention, the principle of which consists in moving the locking device for the lifting-bar from under a tooth thereon without first lifting the load, or, in other words, while the lifting-bar is at rest. I do not limit myself to any particular form or kind of locking-block, which in the preferred form shown is provided with forwardlyprojecting lugs y 1 which respectively pass by opposite sides of the lifting bar, these lugs being between the notched portions of the weighted lever. That portion of the locking-block which is between the lugs is beveled at g on its under side. The guideway for the locking-block may be of any form suitable for the purpose.

In Fig. 9, showing a modification, the hardened-steel ring at which is preferably employed Within the cam-receiving opening of the pawl (even if the ring be fast to the cam forming part of the handle) is made fast in the cam-receiving opening of the pawl.

WVhat I claim is= 1. In a jack, the combination of a standard having a guideway for the lifting-bar and, laterally thereof, a guideway for a reciprocating locking-block with a toothed lifting-bar; a handle fulcrumed 011 the standard; a lifting-pawl pivoted on the handle and movable into and out of engagement with a tooth on the lifting-bar; a reciprocating locking-block mounted in its said guideway and movable into and out of engagement with a tooth on the lifting bar; a lever fulcrumed on the standard and engaging said locking-block; and a weight on the lever and operating to move the lifting-block under a tooth as the lifting-pawl raises the apex of a tooth past the opposed edge of the locking-block.

2. In a jack, the combination of a standard havinga guideway for the lifting-bar and, at an angle thereto, a guideway for a reciprocating locking-block, with a toothed lifting-bar; a handle fulcrumed on the standard; a-lifting-pawl pivoted on the handle and movable into and out of engagement with a tooth on the lifting-bar a locking-block automatically movable into a position under a tooth on the lifting-bar as the lifting-bar is raised; a compound lever fulcrumed on the standard and means for connecting it with the handle when the locking-block is to be moved out of the 1 way of said teeth to permit the automatic fall of the lifting-bar.

3. In a jack, the combination of a standard; a toothed lifting-bar mounted therein; a handle fulcrumed to the standard; a lifting-pawl pivoted to the handle and movable into and out of engagement with a tooth on the lifting-bar; means for automatically locking the lifting-bar in raised position When the liftingpawl is out of engagement with the liftingbar; and means for temporarily connecting the lockin g mechanism with the handle when it is desired to lower the lifting-bar.

4. In a jack, the combination of a standard having a guideway for the lifting bar; a toothed lifting-bar loosely mounted in said guideway; a handle fulcrumed on the standard; a cam on the handle; an upwardly-extending, lifting-pawl pivoted on said cam and movable into and out of engagement with a tooth on the lifting-bar; a horizontally-movable looking-block mounted in a locking-block guideway, in the upper end of the standard; a lever loosely pivoted on the frame and formed with recesses which engage said locking-block; means for automatically actuating the lever to reciprocate it into and out of locking position; a lever member pivoted on said lever; and a hook on the handle-bar for temporary connection of the handle-bar and said lever member.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses, on this 8th day of July, A. D. 1898.

ERVIN T. TREFETHEN;

Witnesses:

EDWARD S. BEACH, ALICE I. CRAWFORD 

